Thermostatic fitting



-2 1938. P. H. THOMPSON. 2D 2,106,668

THERMOSTATIC FITTING Filed Nov. 21, 1935 Patented Jan. 25, 1938 UNITEDSTATES PATENT OFFICE THERMOS TATIC FITTING Application November 21,1935, Serial No. 50,991

'7 Claims.

This invention relates to thermostatic fittings of generalapplicability, but especially designed to be intercalated inrefrigerant-carrying conduits, and corresponding to the temperature ofthe refrigerant within the conduit.

Prior to the advent of the present invention, some manufacturers ofmechanical refrigerators have been content to merely place thethermostat in the refrigerated chamber, where it responds to thetemperature of the refrigerated atmosphere. Others have effected acompromise by clamping the thermostat against the refrigerant conduit,so that it responds to the composite temperature of the refrigerant andthe atmosphere of the refrigerated chamber, but the placing of thethermostatic element in either of these locations is unsatisfactory, forit responds to spurious conditions, such as caused by the momentaryopening of the refrigerator door.

It has been proposed to enclose the thermostatic bulb within therefrigerant conduit, but the means for doing so, up to the present time,have been difficult or expensive'to construct and install, or haveformed an obstacle to the normal fiow of the refrigerant.

The general object of the present invention is to provide a fitting,either of straight or bent form, adapted to be interposed between theadjacent ends of a refrigerant conduit so as to form part of the saidconduit, and enclosing as a unitary part thereof, a thermostatic bulbspaced from the walls of said fitting and having an end constructionwhich minimizes its obstruction to the flow of refrigerant throughtheconduit.

Another object of the invention is to provide a fitting having athermostatic bulb arranged therein and supported laterally from thewalls of said fitting.

A further object of the invention is the provision in a thermostaticfitting, as described, of lateral posts supporting the bulb, thepostsbeing hollow so that one can form a portion of the tube which places thebulb in communication with the control element of the thermostat, whilethe other post may be utilized for filling the bulb and its appurtenantinstrumentalities with the volatile fluid.

Still another object of the invention is to streamline the ends of thebulb so that the flowing refrigerant does not create eddies'and backpressure at the forward end of the bulb, and causing the refrigerant tofollow the surface of the bulb to its rearward end, making thethermostat extremely sensitive to the temperature of the flowingrefrigerant.

A further object of the invention, in connection with that form in whichthe bulb follows the bend of a fitting, is to position the bulb so thatits surface will be angularly impinged by the flowing refrigerant,thereby scouring away any surface film of inert refrigerant whichordinarily would cling to the bulb.

Another object of the invention. is to locate the bulb in the conduitcloser to the bottom wall than to the other walls, so that it will bebathed in a stratum of the denser gas.

Other objects of the invention will appear as the following descriptionof a preferred and practical embodiment thereof proceeds.

In the drawing, throughout the several figures of which the samecharacters of reference have been employed to designate identical parts:

Figure 1 is a longitudinal diametrical section through a straightfitting embodying the principles of the present invention;

Figure 2 is a cross section taken along the line 2--2 of Figure 1; v

Figure 3 is a longitudinal diametrical section through an elbow-shapedfitting;

Figure 4 is a vertical axial section taken at right angles to the viewshown in Figure 3, the

lower portion being broken away;

Figure 5 is a cross section similar to that of Figure 2, but showing aslightly modified form of the invention; and

Figure 6 is a cross section taken along the line stituted by standardend connections 2 and 3,.

which may be similar and, as shown, are threaded and of the solderlesstype, it being understood of course that the construction of theconnections as shown is exemplary only and that any other form may beemployed without transcending the scope of the invention.

Said connections are provided at either inner end with annular rabbets 4and 5, constituting a seat for the ends of the cylindrical section orbarrel 6, which cylindrical section is preferably soldered to the endconnections as is indicated at I.

The end connections are bored as at 8, so as to make the fitting acontinuation of the refrigerant or other conduit in which the fitting isintercalated. The diameter of the intermediate section or barrel 6 islarger than the diameter of the bores 8.

Within the barrel 6 is a thermostatic bulb or capsule 9. This wasinserted into the barrel 6 before the latter was secured to the endconnections 2 and 3, and secured in place within said barrel by means ofposts l and II, which pass laterally from the interior of said barrel tothe exterior through apertures I2 and I3 formed in a wall of the barrel.The posts are suitably secured to the wall of the barrel 5 by solder orany other suitable means. The posts l0 and H are preferably hollow, andone of the posts, for example, the post l9, forms a continuation on theoutside of barrel of the tube M which leads to the expansible motor, notshown, actuated by the thermostatic element.

The thermal insulation of the bulb 9 is assisted by making the posts ofmetal of low conductivity and by restricting their cross section to theminimum area so as to reduce the rate of heat exchange with the metal ofthe enveloping conduit to a minimum. Since it may be desirable toprovide auxiliary support for posts of such restricted cross section,filler pieces 25, see Figure 1, may be provided surrounding the posts I0and II and against which the tube 9 rests. The filler pieces arepreferably of non-conductive material such as a phenolic condensationproduct and they may be streamlined in the direction of flow through theconduit, as indicated at 26 in Figure 6.

The wall of the tube 9 is preferably made as thin as possible so as toobviate any substantial metallic reservoir of latent heat which wouldretard the response of the thermostat to temperature changes of thefluid within the conduit.

The tube II also may be hollow and serves as a means of filling thethermostatic capsule with volatile fluid. Upon completion of the fillingoperation, the post I I is permanently sealed off.

It will be observed in Figure 1 that the opposite ends of the bulb 9 aretapered, coming substantially to a point at IS. The ends of the bulb maythus be described as streamlined, which shape operates to cleave theflowing refrigerant gas so as to prevent eddies and back pressureagainst the anterior end of the bulb 9. The gas thus cleft flows withsubstantially undiminished Velocity, through the annular space l6,between the bulb 9 and the inner surface of the barrel 6, and exits fromthe fitting by way of the end connection 3. The posterior end of thebulb 9 is streamlined so as to direct the flowing gas down close to thesurface of the thermostat in the rear, thereby making the bulbsubstantially one hundred percent efficient in its response totemperature variations of the refrigerant.

Figures 3 and 4 show an elbow fitting adapted to be interposed betweenadjacent ends of a refrigerant conduit and to form a bend in saidconduit. In this form of the invention, the end conections 2 and 3 arethe same as in that form of the invention first described. The barrel2|, as shown, has the form of a long sweeping rightangled curve orelbow. It is soldered to the end connections in the same manner as inFigure 1, and the bulb is likewise streamlined at the ends. The bulb issupported away from the sides of the barrel 2| by the hollow posts l0and II which extend laterally through the side wall of the fitting. Theposts lead respectively to the tube I0 which serves the expansibleelement, not shown, and to a filling source, not shown, by means ofwhich the bulb I8 is charged with volatile fluid, after which the tube ll is sealed off.

The form of the invention illustrated in Figure 3 has the advantage thatthe surface of the bulb is disposed at an angle to the direction of theincoming gas, so that the gas impinges at an angle upon the surface ofsaid bulb, in the zone indicated by the brace l1, scouring this portionof the bulb I8 thoroughly and removing the inert gaseous refrigerantwhich would ordinarily cling to the bulb l8 through skin film. Thismakes the bulb extremely quick in its response to the changes intemperature in the flowing refrigerant.

It is obvious that in constructing that form of the invention shown inFigure 3, the bulb [8, to gether with the posts l0 and II are madesufficiently short to pass into the barrel 2|, are introduced into saidbarrel and the posts aligned with apertures suitably placed in the wallof said barrel and then pushed slightly so as to extend through to theoutside of said barrel where the post I0 is then connected so as to formpart of the tube 24. After the bulb l8 has been filled, the post Il maybe sealed off by pinching it together or by soldering, or in any othersuitable manner.

Figure 5 shows a slight variant of the invention applicable either tothe straight or bent type fitting, in which the bulb I9 is eccentricallymounted within the barrel 20, so as to lie closer to the bottom wall ofthe said barrel than to the other walls. In this position, it is bathedby the stratum of the denser gas passing through the conduit.

It is obvious that the above invention realizes the construction of 'a'thermostatic fitting which is simple and inexpensive to construct,easily installed, and which offers the minimum of resist ance to theflow of the refrigerant gas through the conduit in which it isinterposed. It will be understood to those skilled in the art that thespec1fic details of construction and the arrangements of the parts asherein disclosed and described is merely by way of example and not to beconstrued as limiting the scope of the invention as claimed.

What I claim is:

1. Thermostatic fitting comprising an open ended tube, nipples at theends of said tube and connected thereto, said nipples being threaded forconnection to a conduit, a thermostatic bulb in said tube, postsextending through a wall of said tube in longitudinally spaced relationsupporting said bulb adjacent its ends in spaced relation to the wall ofsaid tube, said posts being hollow and communicating with said bulb, oneof said posts communicating externally of said fitting with anexpansible actuator operated by said thermostatic bulb and the otherbeing sealed havlng served as a means for charging volatile fluid intosaid bulb.

2. Thermostatic fitting comprising a conduit, a thermostatic bulb insaid-conduit, a hollow post Supporting said bulb in spaced relation tosaid conduit, the material of said post being of minimum cross sectionalarea to throttle the exchange of heat through its metallic mass, andauxiliary supporting means comprising spacing pieces of thermallynon-conductive material surrounding said post and engaging said bulb andconduit.

v3. Thermostatic fitting comprising an open ended tube, nipples at theends of said tube and connected thereto, said nipples being adapted forconnection to a conduit, a thermostatic bulb extending longitudinally insaid tube, having wedge-shaped ends confronting the bores of saidnipples, posts extendingthrough a wall of said tube in longitudinalspaced-relation supporting said bulb adjacent its ends in spacedrelation to the wall of said tube, said posts being hollow andcommunicating with said bulb, one of said posts communicating externallyof said fitting with an expansible actuator operated by said thermostat,and the other being sealed, having served as a means for chargingvolatile fluid into said bulb.

4. Thermostatic fitting comprising an open ended tube, nipples at theends of said tube and connected thereto, said nipples being adapted forconnection to a conduit, a thermostatic bulb in said tube, said tube andbulb being curvilinear about a common center, posts extending through awall of said tube in longitudinally spaced relation supporting said bulbadjacent its ends in spaced relation to the wall of said tube, saidposts being hollow and communicating with said bulb, one of said postscommunicating externally of said fitting with an expansible actuatoroperated by said thermostat, and the other being sealed, having servedas a means for charging volatile fluid into said bulb.

5. Thermostatic fitting as claimed in claim 4,

said bulb having wedge-shaped ends confronting bulb and adapted to leadfluid under pressurev therefrom to a thermostatically controlled device,

and an element made of thermally non-conductive material surroundingsaidtube and supporting said bulb in heat insulating relation to themetallic mass of said fitting.

7. Thermostatic fitting comprising an open ended tube, a thermostaticbulb in said tube, posts extending through a wall of said tube inlongitudinally spaced relation supporting said bulb adjacent its ends inspaced relation to the wall of said tube, said posts being hollow andcommunicating with said bulb, one of said posts communicating externallyof said fitting with an expansible actuator operated by saidthermostatic bulb and the other being sealed, having served as a meansfor charging volatile fluid into said bulb.

PARKE H. THOMPSON, II.

